Texas Invasives

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Hemidactylus turcicus

Mediterranean House Gecko

Synonym(s): Mediterranean Gecko,
Class: Reptilia
Order: Squamata
Family: Gekkonidae

Photographer: Wendy VanDyk Evans
Source:

Description

The Mediterranean gecko is a relatively small, 4 - 5 in (10 - 13 cm), species that has become ubiquitous in certain areas of the United States. Unlike any native lizard, geckos have sticky toe pads, vertical pupils, and their large eyes lack eyelids. These geckos are generally light gray or almost white in color, but may have some darker mottling. This species is most easily distinguished from the similar Indo-pacific gecko by its bumpy (warty) skin. The Mediterranean gecko can usually be found preying on insects near external houselights or other forms of lighting on warm nights.

Ecological Threat: Due to their ability to breed rapidly and strong resistance to pesticides, the Mediterranean gecko has been able to establish steady populations all along the Southern United States. These populations are often disjunct, however, which gives hope for native species. Throughout Texas, for example, there are strong breeding populations of Mediterranean geckos found around cities, especially the Houston area, but there are major gaps in the population range through the western parts of Texas and into the panhandle. This leads scientists to believe that the Mediterranean gecko may need human structures and/or possibly cannot survive in dense native forests. Indeed, the geckos appear to be found most commonly within developed areas, but have occasionally have been found in remote areas too (further sampling is needed).

While it is unknown what detrimental effects the Mediterranean gecko causes towards indigenous species, at the very least the consumption of resources and occupation of niches is enough to warrant concern.

Biology: Like most other invasive species, the Mediterranean gecko breeds rapidly. Females are capable of laying multiple clutches of two eggs each throughout the summer. These eggs are laid in cracks and crevices in trees or man-made structures including buildings. Like rodents, the Mediterranean gecko has been aided by human development. It is very common to see the geckos on the sides of buildings under lights catching insects on a summer night.

History: It is uncertain how the Mediterranean gecko first made its way to the United States. It was first reported in Key West, Florida 1915. It is thought that this gecko was probably a stowaway on a ship from the Mediterranean area. Mediterranean geckos are quite common in the pet trade, which has no doubt led to its spread across the United States. Currently, this species has high numbers in Florida, and has established breeding populations all along Southern states.

U.S. Habitat: A nocturnal species, Hemidactylus turcicus can be found in cracks and crevices, either man-made or natural, throughout the day, emerging at night to feed on insects and other invertebrates.

Distribution

Native Origin: As the name suggests, the Mediterranean gecko is an Old-World species native to Southern Europe and Northern Africa.

U.S. Present: The Mediterranean gecko has firmly established populations in Florida and the Florida Keys and has also spread to other states such as: Arizona, California, Louisiana, Alabama, Texas, and is expected to continue north.

Distribution in Texas: Hemidactylus turcicus has been recorded throughout much of East and South Texas, but notable gaps exist in its distribution, such as the apparent absence from the panhandle with the exception of Lubbock County.

SIMILAR SPECIES

May be confused with the Indo-Pacific Gecko, Hemidactylus garnotii, although the Mediterranean gecko has bumpy skin while the Indo-Pacific gecko has smooth skin.

Management

Possibly because it is unclear whether there are any long-term negative effects associated with the Mediterranean gecko invasion, not much action has been put into the gecko's management. What is known, however, is that the gecko is strongly resistant to insecticides and other pesticides, so their use is not recommended. ***These geckos are not venomous or aggressive, and are easy to capture by hand. If they do bite, the bite is weaker than that of a native anole lizard and should not raise concern.***

Text References

Farallo, VR, Swanson, RL, Hood, GR, Troy, JR, and MRJ Forstner. 2009. New county records for the Mediterranean house gecko (Hemidactylus turcicus) in Central Texas, with comments on human-mediated dispersal. Applied Herpetology 6(2009) 196-198.

Selcer, Kyle. 1986. Life history of a successful colonizer: the Mediterranean Gecko, Hemidactylus turcicus, in Southern Texas. Copeia 1986(4): 956-962.